EtaMesonNet Meeting 14/10/2004 Status of KLOE and DAFNE Cesare Bini (Universita’ “La Sapienza” and INFN Roma) For the KLOE collaboration 1. Overview of physics at a φ - factory 2. The collider DAFNE 3. The KLOE experiment 4. Overview of KLOE results |Vus| from K L decays Hadronic corrections to g-2 5. Conclusions and Outlook
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EtaMesonNet Meeting 14/10/2004
Status of KLOE and DAFNE
Cesare Bini (Universita’ “La Sapienza” and INFN Roma)
For the KLOE collaboration
1. Overview of physics at a φ - factory2. The collider DAFNE3. The KLOE experiment4. Overview of KLOE results
|Vus| from KL decaysHadronic corrections to g-2
5. Conclusions and Outlook
1. Overview of Physics at a φ - factoryDAFNE: e+e- collider at center of mass energy W=1020 MeV
at Laboratori Nazionali di Frascati INFN
W=1020 MeV φ meson peakσ(e+e- φ all) ~ 3 µb
W scan around the φ peak ( φ KSKL )
Why at the φ peak ? Because it is “a source of interesting physics”BRs of φ decay channels (from PDG)
Kaon physics:monochromatic ( p = 110 MeV/c ) kaons (charged and neutrals);“coherent” production mutual “tagging”Neutral kaons are produced in a pure quantum JPC = 1−− state:λS = 6 mm λL = 3.5 m
( ) ( ) ( ) ( )[ ]( ) ( ) ( ) ( )[ ]pKpKpKpKN
pKpKpKpKi
SLLSrrrr
rrrr
−−−=
−−−=
2
21 0000
Pure KS and KL beams KS , KL physicsKaon interferometryHigh statistics of K± ; K± decays and asymmetries
3 pionsφ ρπ samples of ρ+, ρ- and ρ0 CPT and Isospin testsStudy of direct φ π+π−π0 coupling
Radiative decays (1):
Since φ = <ss> state (almost pure)φ Mγ is related to the s-content of M
Nature of scalar mesons ( f0(980), a0(980), σ )Pseudoscalar mixing angle ( comparison of φ ηγ and φ η’γ )
Pb-Sci.Fi. StructureLight guides + PMT read-outEnergy, Time and impact position
measurements.
)(%7.5)(
GeVEEE
=σ
psGeVEpst 140
)(54)( ⊕=σ
The KLOE Drift Chamber“Light” mechanical structure (carbon fiber) < 0.1 X0Gas Mixture = 90% He – 10% Isobut. / All stereo wires zHit position measured with σ( r ) ~ 200 µm and σ( z ) ~ 2 mm
σ(p)/p ~ 0.3-0.4%
p(MeV/c) resolution for 510 MeV/celectrons and positrons
Polar angle
M(MeV/c2) resolution for Ks π+π-
σ(M) ~ 1 MeV/c2
M(π+π-) (MeV/c2)
KLOE Data Taking1.Continuous data taking: no stop at beam injection;2.Trigger: ≥ 2 energy clusters above threshold (50 – 150 MeV)
OR > NNN hits in the drift chamberTrigger Rate (kHz) = 1 (physics) + 0.9 (Cosmic rays) + 0.45 (Bckg) = 2.3 kHz
0.0
0.5
1.0
1.5
3.On-line calorimeter calibration: (every 200 nb-1 ~ 1 h)Energy (absolute scale from e+e- γγ)Time (absolute scale using DAFNE RF signal (2.715 ns))
Time (2002 d.t.)
Rel. energyVariations (%)
EndcapsBarrel
4.Drift Chamber t0s and space-to-time relations calibration:Iterative procedure based on cosmic ray runs;On-line check of residuals using Bhabha and cosmic rays
s-t relations residuals vs drift distance
On-line check of residualswith selected Bhabha events
5. Data quality controlOn-line reconstruction evaluation of relevant quantities run by run:
W (MeV) pφ (MeV)
xV (cm) zV (cm)
Run Number
These variables are used in the data reconstructionprocedure and to provide information to the DAFNE team.
W=√s center of mass energy
pφ φ momentum (lab. boost)
xV , yV, zV interaction point coordinates
6. Data reconstruction:End of run: if (calibration_ok) start Data reconstruction
Big computing effort;~ 120 CPU used ~ 300 TB tapes (including raw data, DST files and MC events)
4. Overview of KLOE results
KS→ πeνPhys. Lett. B535 37 (2002)Preliminary update presented at ICHEP ‘04
KS → π+π−(γ)KS → π0π0
Phys. Lett. B538 21 (2002)Update with ’01-’02 data in progress
KL → γγ/KL →3π0 Phys. Lett. B566 61 (2003)K+ → π+π0π0 Phys. Lett. B597 2 (2004)
K0 mass KLOE Note 181 (http://www.lnf.infn.it/kloe)Upper limit BR(KS →π0π0π0) Paper in preparation
KL→πµν,πeν,π+π-π0,3π0 Preliminary results presented at ICHEP ‘04Vus from KL and KS Preliminary results presented at ICHEP ’04KL mean life Preliminary results presented at ICHEP ‘04
Vus from K± In progress
CP violation & interference In progress
(1) Kaon physics
φ → π0π0γPhys. Lett. B537 21 (2002) Updates in progress
Upper limit BR(η →3γ) Phys. Lett. B591 45 (2004)
φ leptonic width Paper in preparation
BR(η → π0γγ) Preliminary results presented at ICHEP ‘04
Search for f0(980) π+π− Preliminary results presented at ICHEP ‘04Hadronic cross section(down to 2Mπ
2=0.08 GeV2) In progress
Hadronic cross section(0.35 < s < 0.95 GeV2) Paper submitted to Phys. Lett. B
Upper limit BR(η → π+π-) Paper in preparation
φ → ηπ0γPhys. Lett. B536 209 (2002) Updates in progress
φ→ η’ γ, ηγ (mixing angle)
Phys. Lett. B541 45 (2002) Updates in progress
φ → ρπ, π+π-π0 Phys. Lett. B561 55 (2003)
Dalitz plot η → 3π Preliminary results presented at ICHEP ‘04
(2) Other results (radiative decays…)
KLOE contributions to 2 frontier problems in high energy physics:(1) Unitarity of the CKM matrix through Vus precision measurement(2) Hadronic corrections to the muon anomaly aµ
|Vud | is extracted from nuclear β decay (Czarnecki-Marciano-Sirlin hep-ph/0406324)
|Vus | is extracted from partial widths of kaon semileptonic decays Γ(K πlν(γ));
(1) Unitarity Test: Vus
At present the most precise test of unitarity of CKM matrix comes from 1st